Conventionally, a limiter circuit for limiting an upper limit or a lower limit or upper and lower limits of an analog signal inputted is widely used in a semiconductor integrated circuit for the purposes of removing noise components, protection and operational stability of the circuit, and also analog signal processing. FIG. 17 shows an ideal diode circuit widely used as limiter circuit. An ideal diode circuit 70 includes diodes D1, D2, D3, D4, differential amplifiers Q71, Q72, and resistors R71, R72.
FIG. 18 shows an example of operation of the ideal diode circuit 70. When an input signal Vin with a waveform as shown in FIG. 18(a) is applied, and when the input signal Vin is larger than an upper limit threshold signal VH, the diode D1 becomes ON, the diode D2 becomes OFF, and voltage Vn20 at node N20 becomes equal to VH. When the input signal Vin is smaller than the upper limit threshold signal VH, the diode D1 becomes OFF, the diode D2 becomes ON, and voltage Vn20 at node N20 becomes equal to the input signal Vin.
Similarly, when node N20 is smaller than a lower limit threshold signal VL, the diode D3 becomes ON, the diode D4 becomes OFF, and an output Vout becomes equal to the lower limit threshold signal VL. When voltage Vn20 at node N20 is larger than the lower limit threshold signal VL, the diode D3 becomes OFF, the diode D4 becomes ON, and the output signal Vout becomes equal to the voltage Vn20 at node N20.